Willpower

Willpower -"Willpower increases the size of the mana pool for mages or the stamina pool for warriors and rogues."

What we think: The importance of Willpower can vary from person to person; it all depends on how you play your class. Mages might want to consider putting points into Willpower since a deeper mana pool translates into a higher damage output. The same logic applies to rogues and warriors as well, but to reiterate the point, the case rests on the kinds of abilities you have and how you play your characters.